This invention relates to a window and more particularly to a window having one or more sliding sash which are pivotable about an axis substantially at the sash mid-point for convenience in cleaning the sash exterior.
Vertical and horizontal sliding windows are well known. Typically a sliding window has one or more sash, usually two, mounted in a frame. One or both of the sash are adopted for sliding in the frame. To prevent or minimize air and water infiltration, weather-stripping is provided between all of the movable and fixed frame members and between meeting sash members.
Typically, the window exterior is cleaned from the exterior, but an ever increasing number and particularly residential windows, are adapted so that the exterior of the sliding sash can be cleaned from the building interior. Some are adapted so that the sash can be removed from the frame while others enable the sash to be tilted, rotated, or swung into the building interior. Gurniak U.S. Pat. No. 3,041,680, for example, shows a horizontal sliding sash which can be swung into the interior. As the sash is slid in the frame and approaches the full extent of its opening, it is cammed upwardly to be out of retention of the frame and a hinge arrangement between the frame and sash stile enables the sash to be swung inwardly for cleaning. Although such a pivotable arrangement may be more convenient than lifting and removing the sash, it has its disadvantages as well. It may be seen as well that the total weight of the sash is borne by the swing mechanism. If the sash is large, the weight can be substantial and create concentrated forces on the mechanism to cause failure or spring the mechanism in a manner that problems in aligning the sash for closing arise. Since the total width of the sash swings inwardly, cleaning may require moving furniture before the sash can be swung inwardly. Travis U.S. Pat. No. 2,744,296 shows a sash which pivots about a central axis which is an improvement in the sense that less room is required to gain access to the sash exterior. Also, there is far less less load or strain on a center-pivot mechanism than one that supports the weight at a stile connection. Travis, however, does not describe a sliding window. The sash is adapted for side movement, but only to the extent required to clear one of the stiles from the frame so that the sash can be rotated. Furthermore, to provide seals against water and air infiltration, Travis' window requires bars on the head and sill members which have to be moved vertically clear of the sash before it can be pivoted. Travis does not make a suggestion of any kind for providing a sliding center-pivoted sash.
Jones et al U.S. Pat. No. 3,105,576 is the only patent noted which describes a window having a center-pivoted sash which also slides. Jones at al teaching, however, is directed only to a vertical double hung-window and makes no suggestion for constructing a horizontal sliding window having center-pivoted sash. Although the Jones et al proposal of providing a center-pivoted sliding sash is advantageous the teaching is directed only to vertical sliding double-hung window. Furthermore, the design proposed by Jones et al requires that the sash be removable from the frame which negates providing a positive interlock between between the sash and frame. The advantages a such a positive interlock will be explained in greater detail in the following discussion of the present invention. It would be desirable, therefore, to provide a center-pivoted sliding window having features which may be used to advantage in either a horizontal or vertical sliding window.